ucg/docsite/site/content/stdlib/lists.md

+++ title = "List Operations" weight = 1 sort_by = "weight" in_search_index = true +++

The UCG list modules can be imported like so let l = import "std/lists.ucg"; It has a number of useful operations.

reverse

The reverse module reverses a list. It has a single required parameter:

• list the list to reverse.

let l = import "std/lists.ucg";
l.reverse{list=[1, 2, 3]} == [3, 2, 1];

str_join

The str_join module joins a list with the string representation of each element. It has two parameters:

• list which is required. The list to reverse.
• sep which is optional and defines the separater to use when joining the elements. Defaults to a single space

let l = import "std/lists.ucg";
l.str_join{
    sep=" ",
    list=[1, 2, 3]
} == "1,2,3";

len

The len module returns the length of a list. It has a single required parameter.

• list The list to reverse.

let l = import "std/lists.ucg";
l.len{list=[0, 1, 2, 3]} == 4;

enumerate

The enumerate module enumerates the elements of a list. It has three parameters.

• list which is required and is the list to enumerate.
• start which is optional and defines the start number of the enumeration. (defaults to 0)
• step which is optional and defines the step amount for the enumeration. (defaults to 1)

let l = import "std/lists.ucg";

// with defaults
l.enumerate{list=[1, 2, 3]} == [[0, 1], [1, 2], [3, 4]];

// With all parameters
l.enumerate{
    start=1,
    step=2,
    list=["foo", "bar", "foobar"],
} == [[1, "foo"], [3, "bar"], [5, "foobar"]];